Apparatus for grooving a concrete slab

ABSTRACT

Concrete pavement is provided with transverse grooves in its surface by a forming device having projecting parallel ribs that are pressed into contact with a concrete slab while in plastic or formable state and moved along the slab surface between opposite edges thereof to form parallel grooves in the surface of the slab. Retractable support forms are provided at opposite edges of the concrete slab to support the slab during the grooving operation. The forms have grooved upper surfaces aligned with the top surface of the slab, and the grooves in said surfaces conform with the ribs on the groove forming device, thereby allowing the device to be drawn beyond the edge of the slab. In the alternative, the forms may have a resilient upper surface to accommodate the ribs of the grooving device. The apparatus may include a mechanism for moving the support forms into proper position against the edges of the slab with each pass of the grooving device, as well as a mechanism for laying a strip of plastic material between the forms and the slab to prevent adherence therebetween.

United States Patent [1 1 Perkins [4 1 Oct. 23, 1973 1 APPARATUS FOR GROOVING A CONCRETE SLAB [76] Inventor: Glen E. Perkins, 1800 7th St., Rock lsland, lll.

[22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,256

[52] U.S. Cl 425/385, 94/45 R, 425/293 [51] Int. Cl 829d 7/22 [58] Field of Search 94/45 R; 425/427, 425/385, 293, 295, 299, 303, 304, 291

[56] References Cited UNITED STATES PATENTS 3,516,340 6/1970 Perkins 94/45 R 3,470,924 11/1969 Short 144/133 R 3,540,359 11/1970 Swisher et a1... 94/46 R 3,423,859 1/1969 Swisher et al. 94/46 R 3,230,843 1/1966 Satucci 94/46 R X 3,098,413 7/1963 Guntert et al... 94/45 R X 3,516,339 6/1970 Perkins 94/45 R Primary Examiner-H. A. Kilby, Jr. Attorney-Lee J, Gary et al.

[ ABSTRACT Concrete pavement is provided with transverse grooves in its surface by a forming device having projecting parallel ribs that are pressed into contact with a concrete slab while in plastic or formable state and moved along the slab surface between opposite edges thereof to form parallel grooves in the surface of the slab. Retractable support forms are provided at opposite edges of the concrete slab to support the slab during the grooving operation. The forms have grooved upper surfaces aligned with the top surface of the slab, and the grooves in said surfaces conform with the ribs on the groove forming device, thereby allowing the device to be drawn beyond the edge of the slab. 1n the alternative, the forms may have a resilient upper surface to accommodate the ribs of the grooving device. The apparatus may include a mechanism for moving the support forms into proper position against the edges of the slab with each pass of the grooving device, as well as a mechanism for laying a strip of plastic material between the forms and the slab to prevent adherence therebetween.

7 Claims, 5 Drawing Figures APPARATUS FOR GROOVING A CONCRETE SLAB BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for grooving concrete slabs and more particularly to a method and apparatus for transversely grooving a plastic concrete slab along parallel lines extending completely between the side edges of the slab.

The present invention provides improvements to the method and apparatus disclosed in my U.S. Pats. Nos. 3,516,339 and 3,516,340, incorporated herein by reference. As disclosed in said patents, it has become desirable or necessary to provide either transverse grooves or longitudinal grooves in concrete pavement, in order to minimize skidding or hydroplaning of the wheels of a vehicle on the finished pavement under wet conditions. Said patents disclose paving apparatus including a forming plate or extrusion meter having projecting parallel ribs on its lower surface, and means for pressing the plate against the surface of the slab while the concrete is still plastic or formable and for moving the plate along the slab to extrude parallel grooves of the desired shape in the concrete surface.

In use of the apparatus described above, a problem is encountered in extending the grooves completely to the edges of the slab. Since the slab is in a plastic condition, the edges must be supported by slip forms or the like to prevent the concrete from slumping away from the extruder plate. At the same time, the presence of the slip forms prevents the extruder plate from traveling completely to the edges of the slab. In U.S. Pat. No.

3,516,339, for example, the extruder plate must be lifted from the slab when the slip form is encountered, and suction between the extruder plate and the slab may cause undesirable irregularities or pockets near the edge of the slab.

BRIEF SUMMARY OF THE INVENTION The present invention overcomes the above problems by providing a side form or edge support having an upper surface that conforms to or in conformable with the shape of the extruder plate. In this manner, the extruder plate may be drawn past the edge of the slab over the edge support and thereby form grooves which extend completely to the edge. In one embodiment, the upper surface of the side form or edge support is grooved in conformity with the ribs on the extruder plate; and in a second embodiment, the upper portion of the edge support comprises a strip of resilient material that yields under the pressure of the ribs on the extruder plate, thereby accomplishing the same result.

The invention also provides an improved transverse grooving machine that is independent of the paving machinery and that can be propelled to a section of paving to be grooved, whereupon side forms or edge supports can be moved into parallel abutting relationship with the opposite sides or edges of the slab, with the top of the forms flush with the top of the slab. The extruder plate is then engaged with the conformable upper surface of one of the edge forms and passed over the slab and beyond the opposite edge form. The edge forms are then moved away from the slab, and the machine advanced to the next adjacent section of the slab, whereupon the sequence is repeated for grooving succiessive portions of the slab.

Other advantages and features of the invention will become manifest in the following detailed description.

THE DRAWINGS FIG. 1 is a plan view of the grooving apparatus of the present invention;

FIG. 2 is a fragmentary sectional view taken through line 22 of FIG. 1;

FIG. 3 is a vertical sectional view of the extruder plate engaging one of the grooved edge supports;

FIG. 4 is a view similar to FIG. 3, but showing the use of a resilient strip at the top of the edge support; and

FIG. 5 is a fragmentary perspective view of a grooved concrete slab prepared in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The grooves forming component utilized in the present invention generally comprises a forming member (such as the extrusion plate of my U.S. Pat. No. 3,516,340 or the roller of my copending application Ser. No. 120,636, filed Mar. 3, 1971 having a plurality of projecting ribs that are pressed into the plastic surface of a concrete slab to form parallel grooves therein. Means are provided for moving said member across the slab between and beyond its opposite edges. Said opposite edges are supported by a pair of members having upper surfaces that are conformable with the ribbed surface of the forming member, thereby allowing the member to be moved beyond ghe edge of the slab.

The grooving apparatus may for example be conveyed by a pair of endless tracks 10 and 12, which are located beyond opposite respective edges 14 and 16 of the slab 18. Longitudinal frame members 20 and 22 are secured to the track members 10 and 12, and a pair of transverse frame members 24 and 26 are secured between the members 20 and 22 to extend above and across the slab l8 and to support the controls 28 for the machine and the grooving member, here shown as extrusion plate 30.

As shown in FIGS. 1 and 2, the extruder plate 30 is carried by a movable beam 31 which extends between and is guided on the transverse members 24 and 26 and is driven from one side of the apparatus to the other by anendless belt or chain 32 (FIG. 2) within each of the transverse members, said chain being wrapped around sprockets 34 at the ends of each transverse member and being suitably driven in both directions by the drive 28. The transverse members 24 and 26 are sufficiently long so that the beam 31 and the extruder plate 30 may be moved across the entire width of the slab l8 and beyond both edges 14 and 16 thereof. Hydraulic cylinders 36 suspend the extrusion meter from the movable beam and are operable to provide variations in pressure between the plate and the surface of the plastic slab l8, and to allow lifting of the extruder plate after it has completed a pass and as it is being returned to its starting position. v

A pair of movable side forms 38 and 40 are movable inwardly to embrace the respective edges 14 and 16 of the slab. The side forms 38 and 40 are mounted for movement with the apparatus so as to be alignable with the slab edges at successive portions of the slab. A lever 42 is pivotally connected at one end to the rear transverse member 26 and pivotally connected at the other end to a pair of arms 44 and 46; the opposite end of the arms are in turn connected to a side form 38 or 40. This feature allows the side forms to be automatically aligned with the edges of the slab when pressed against said edges.

A double acting hydraulic cylinder 48 is connected between a longitudinal member 20 or 22 and the lever 42 such that both of the forms 38 and 40 may be moved from a retracted position into firm compressive engagement with the edges of the slab and thereby support the plastic slab during the grooving operation. Without the side forms 38 and 40, the plastic slab would be slumped or deformed toward the direction of movement of the extruder plate 30. The side forms 38 and 40 are also adjustable vertically to move the top surfaces thereof flush with the slab surface.

As mentioned previously, the presence of side forms in prior art teachings hindered the movement of the extruder plate to the edge of the slab, with the result that the grooves imparted in the slab did not extend completely to the edge. As shown in FIGS. 3 and 4, the bottom surface of the extruder plate 30 comprises a plurality of spaced parallel ribs 44 which form the grooves 46 (FIG. in the slab surface. In order to operate properly, the leading edge 48 of each of the ribs 44 is tapered from the base of the extruder plate. Accordingly, it may be seen that if the plate could travel no. further than the edge of the slab, the grooves in an area adja cent the edge would be incompletely formed.

The above problem is overcome by the provision of means to allow movement of the extruder plate 30 past the edge of the slab while providing the essential support function. For this purpose, the top surfaces of the edge forms 38 and 40 are adapted to accommodate the ribs 44 of the extruder plate 30, which allows the plate to pass over and groove the slab in a continuous motion from an initial position beyond one edge of the slab to a second position beyond the opposite edge of the slab without lifting the plate, as shown in FIG. 2.

In a preferred embodiment, as shown in FIG. 3, the ribs 44 of the extruder plate 30 are accommodated by providing the top surface of each of the edge forms 38 and 40 with a plurality of grooves 50 that conform to said ribs and eliminate obstruction of the extruder plate. Preferably, the side forms 38 and 40 are wider than the extrusion plate and the top surface of the form between adjacent grooves is flush with the slab surface. In this manner, the slab may be completely grooved from one edge to another without any substantial sacrifice of support. The respective grooves of the opposite forms 38 and 40 are aligned along transverse lines to assure uniformity in the grooving operation.

As an alternative, shown in FIG. 4, the top of the side forms 38 and 40 may comprise resilient pads 52 of sufficient thickness to accommodate passage of the extruder plate without lifting of the plate. The top surfaces of the pads 52 are normally in register with the slab surface but may be deformed under pressure of the ribs 44 of the extruder plate 30.

The result of the present invention is that grooves 53 formed in the slab 18 will extend completely and cleanly to its edges without the necessity of raising the extruder plate, as shown in FIG. 5. Also, since the side loems embrace the slab edges during the entire grooving operation, there is no concern about disrupting the level surface of the slab.

In order to prevent the side forms 38 and 40 from becoming stuck to the slab edges while in compressive engagement therewith, means may be provided for automatically laying a strip of sheet plastic or similar material between each of the forms and the corresponding slab edge, as shown in FIG. 1. A roll of plastic material 54 may be rotatably mounted about a vertical axis on the forward transverse member 26 adjacent the slab edge, along with means for unrolling the sheet against the slab edge. The recited means, for example, may comprise a first roller 56 mounted on the transverse member 26 beyond the edge of the slab, a second roller 58 engageable with the slab edge and rotatably mounted on the end of a lever 60, the other end of which is pivotally mounted on said transverse member between the material roll and the first roller. A retractable cylinder 62 is connected between the lever and the transverse member, such that the second roller 58 may be pressed against the slab edge. The plastic strip is then passed from the roll 54 around the first roller 56 and the second roller 58 and is passed around the latter roller against the slab edge. In this manner, the strip is automatically unwound and placed against the slab edge as the device progresses in its normal direction of movement, as indicated by the arrow in FIG. 1.

In order to assure uniformity in the grooving process, it is important that the transverse members 24 and 26 be maintained parallel to the slab surface in order that the action of the extruder plate will be uniform. To assure this result, sensing devices, such as variable switching devices 64 having a pivotally mounted arm 66 engaging the slab surface may be mounted on the leading side of the transverse member 26, said switching devices being operable to maintain a constant distance between the top of the slab and the transverse members. Preferably, the switching devices 64 are located near each edge of the slab to assure proper levelling of the apparatus.

An important feature of the present invention is that the apparatus is capable of continuous grooving of the slab. When in proper position, the machine is stopped, the side forms 38 and 40 are brought into firm engagement with the edges of the slab, the extruder plate 30 is pressed against the top of one side form and then passed across the slab. The side forms may then be retracted, the plastic strip material between the side forms and the slab preventing a suction action and providing for ready retraction of the forms from the slab while maintaining the slab edge upright and unde-. formed.

With the forms retracted and the extruder plate raised, the apparatus can be moved forward, which causes plastic strip material to be unwound from the rolls 54 and deposited on the edges of the slab. As the machine moves forward on its endless tracks 10 and 12, along a line parallel to the slab edges, the apparatus is automatically leveled relative to the next successive position of the slab by means of the sensing devices 64. The apparatus is moved in the direction of the arrow shown in FIG. 1 to an adjacent ungrooved area, whereupon the machine is stopped, the side forms are again pressed against the slab edges and the extruder plate is pressed against the upper surface of one form and passed across the slab surface in a compressed relationship therewith beyond the edges of the slab.

When grooving a flat or symmetric slab, the extruder plate may be moved in opposite directions on successive passes. However, where a slab is tilted or sloping, the extruder plate is always operated from the lower edge to the upper edge of the slab to prevent slumping of the slab during grooving. Thus, between passes, as

the machine is advancing, the extruder plate is picked up by the hydraulic cylinders and returned from the upper edge of the slab to the lower edge. This is especially important in airport runway construction.

In this application, I have shown the extruder plate 30 to be the preferred grooving instrumentality. However, the rotary grooving roller shown in my copending application, Ser. No 120,636, filed Mar. 3, 1971, could be used with equal facility.

Also, the transporting vehicle comprising the tracks -12 and the frame members -26 could be replaced by the tractive vehicle shown in U.S. Pats. Nos. 3,423,859; 3,533,337 and 3,540,359; which vehicle comprises a frame adapted to straddle a concrete slab, a tractive element such as a driven track or wheel at each of the four corners of the frame, hydraulic cylinders mounting each tractive element for vertical adjustment, and feeler or sensing devices at each corner for adjusting the respective tractive element to maintain the frame, or the grooving member support elements thereof, parallel to the top of the slab.

Accordingly, while I have shown and described what I regard to be the preferred embodiment of my invention, it will be understood that various changes, rearrangements and modifications can be made therein without departing from the scope of the invention.

Having thus described the invention, what is claimed 1. Apparatus for grooving a plastic concrete slab comprising grooving means having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means transversely across the slab surface in engagement therewith and beyond at least one of the opposite edges of the slab, and support means at said one edge of said slab, said support means engaging and supporting the edge of the slab and having means at its upper surface substantially flush with the surface of the slab accommodating passage of said rib means beyond the edge of said slab and said support means without lifting said grooving means, whereby grooves are formed in said slab surface entirely to at least one edge thereof and wherein said support means has grooves extending across the upper surface thereof accommodating passage therethrough of said rib means.

2. The apparatus according to claim 1 in combination with a frame extending across said slab and movably supporting said grooving means, means adjustably mounting said support means on said frame, and means for moving said support means toward and away from respective opposite edges of said slab.

3. The apparatus according to claim 2 in combination with means for levelling said frame and support means relative to said slab.

4. The apparatus according to claim 3 wherein said means for levelling said frame comprises sensors mounted on said frame and contacting the surface of said slab.

5. The apparatus according to claim 1 wherein means are provided for laying a strip of release material between said support means and the corresponding slab edge.

6. Apparatus for grooving the surface of a plastic slab comprising a frame extending over the surface of the slab and extending beyond opposite edges thereof, means for moving said frame longitudinally of said slab surface, grooving means mounted on said frame having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means on said frame transversely of the slab between and beyond the opposite edges of the slab, and support means mounted on said frame and movable toward and away from the slab for selective engagement with the opposite edges of the slab, said support means including means on the upper surface thereof accommodat-- ing passage therethrough of said rib means for accommodating movement of said grooving means beyond the edges of said slab without lifting said grooving means.

7. Apparatus for grooving a plastic concrete slab comprising grooving means having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means transversely across the slab surface in engagement therewith and beyond at least one of the opposite edges of the slab, and support means at said one edge of said slab, said support means engaging and supporting the edge of the slab and having a resilient portion on its upper surface substantially flush with the surface of the slab accommodating passage of the rib means without lifting said grooving means, whereby grooves are formed in said slab surface entirely to at least said one edge thereof. 

1. Apparatus for grooving a plastic concrete slab comprising grooving means having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means transversely across the slab surface in engagement therewith and beyond at least one of the opposite edges of the slab, and support means at said one edge of said slab, said support means engaging and supporting the edge of the slab and having means at its upper surface substantially flush with the surface of the slab accommodating passage of said rib means beyond the edge of said slab and said support means without lifting said grooving means, whereby grooves are formed in said slab surface entirely to at least one edge thereof and wherein said support means has grooves extending across the upper surface thereof accommodating passage therethrough of said rib means.
 2. The apparatus according to claim 1 in combination with a frame extending across said slab and movably supporting said grooving means, means adjustably mounting said support means on said frame, and means for moving said support means toward and away from respective opposite edges of said slab.
 3. The apparatus according to claim 2 in combination with means for levelling said frame and support means relative to said slab.
 4. The apparatus according to claim 3 wherein said means for levelling said frame comprises sensors mounted on said frame and contacting the surface of said slab.
 5. The apparatus according to claim 1 wherein means are provided for laying a strip of release material between said support means and the corresponding slab edge.
 6. Apparatus for grooving the surface of a plastic slab comprising a frame extending over the surface of the slab and extending beyond opposite edges thereof, means for moving said frame longitudinally of said slab surface, grooving means mounted on said frame having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means on said frame transversely of the slab between and beyond the opposite edges of the slab, and support means mounted on said frame and movable toward and away from the slab for selective engagement with the opposite edges of the slab, said support means including means on the upper surface thereof accommodating passage therethrough of said rib means for accommodating movement of said grooving means beyond the edges of said slab without lifting said grooving means.
 7. Apparatus for grooving a plastic concrete slab comprising grooving means having projecting rib means thereon for forming grooves in the surface of the slab, means for moving said grooving means transversely across the slab surface in engagement therewith and beyond at least one of the opposite edges of the slab, and support means at said one edge of said slab, said support means engaging and supporting the edge of the slab and having a resilient portion on its upper surface substantially flush with the surface of the slab accommodating passage of the rib means without lifting said grooving means, whereby grooves are formed in said slab surface entirely to at least said one edge thereof. 